Nearly three billion people worldwide rely on solid fuel combustion to meet basic domestic energy needs. Most of this combustion, typically found among the poorest populations, takes place using inefficient and poorly vented indoor cookstoves burning biomass (wood, animal dung, crop residues) and coal, resulting in extremely high indoor air pollution concentrations. Improved, more fuel efficient and cleaner-burning, stove designs have the potential to substantially reduce indoor air pollution exposures. However, quantitative assessments of improved stove exposure and health impacts are limited. Indoor air pollution from biomass and coal combustion accounts for an estimated 1.6 million premature deaths per year worldwide, representing about 3% of the global disease burden. These estimates are based primarily on respiratory effects. In order to capture the full burden of disease (and potential benefit), cookstove research will need to incorporate a broader range of health endpoints utilizing methods that are feasible in a rural field setting and in countries with often limited healthcare infrastructure. Furthermore, previous studies, if they have incorporated quantitative pollution measurements at all - have primarily measured fine particulate matter (PM2.5) and carbon monoxide (CO); more detailed quantitative exposure assessment is necessary to inform stove design and priorities. Here we propose a cross-sectional study incorporating innovative methods to measure subclinical markers of cardiopulmonary and metabolic health as well as intensive exposure assessment. Our central hypothesis is that users of improved, cleaner burning stoves will experience better health status compared to users of traditional open-fire cookstoves. We propose the following specific aims: 1) Conduct novel exposure and health measurements in a population consisting of current traditional, open fire users and cleaner-burning stove users and 2) Evaluate the cross-sectional association between stove use (traditional vs. cleaner-burning stoves) and measured indoor and personal pollution with indicators of cardiovascular and metabolic health. Global dissemination of efficient, cleaner-burning stoves has the potential to dramatically improve the health of humans and the environment. This might appear to be a straightforward solution. However, a critical gap remains in that comprehensive evaluations of exposures and health impacts are still necessary to encourage and justify large-scale stove intervention programs. This project, incorporating novel health and exposure measures and establishing the feasibility of these measures in field settings, will contribute to our knowledge f the impacts of biomass combustion and provide preliminary evidence to support the development of larger- scale randomized trials, thereby enabling us to leverage its impact for future studies. Given the ubiquity of indoor biomass smoke exposures around the world and the increasing prevalence of these chronic diseases in developing countries, further evaluation of the impact of improved stoves is needed in order to fully assess the burden of this exposure.